SE5 KK-OZ1320

I looked at using plasterboard when I first made the building board but decided against it.
It isn't cheap anymore. nothing is, & my experience of it is it crumbles round the edges & makes a lot of mess, I am working in the house so have to avoid treading stuff into the carpet. I am also sure I couldn't carry it in the car without damaging it.
The cork now seems to have settled down. The Danish Oil must be filling the pores in the cork.

This morning I decided I needed to get some balsa cement for fixing the struts, They sit at an angle so I thought they needed something bulkier than the SuperPhatic. So I ordered two tubes & a sheet of 1/32nd on click & collect frome Hobbycraft.
When I looked at the balsa at home it seemed thick so I measured it. It is 1.5mm, its obviously wrongly labelled 1/16th. I've complained & asked for a refund, it would cost me more in petrol to take it back. I'll see how they respond.

 

This is the first loose assembly, without the wheels & outer struts, the next stage is to paint it before it can be glued together. There are a couple of paint schemes on OuterZone, it seems the choice is 50 shades of kahki. On ebay the choice of tubs of acrylic is 69ml or 500ml with a similar difference in price.
There is a large amount of wash-out on the right-hand upper wing so I've got to see what I can do about that.
I wanted to sheet the nose in balsa rather than card, which is what I wanted the 1/32nd for. I tried to use the 1/16th that Hobbycraft supplied but it is very hard. When I soaked it & rolled it into a cylinder it was twisted & I couldn't get it to straighten out. I allowed it to dry out but then it just cracked so I've used the softest sheet of the ten I bought earlier. This has worked OK and I've pasted tisuue onto it to strengthen it.
By the way I got the £3 refund.
I definitely needed the balsa cement for the struts, all the surfaces were at an angle, the Superphat would have just run off.
The KK design has a long cut-out on the fuselage sides. I assumed it was to accomodate the struts so I shortened them to just let in the the struts but in fact the struts just rest on the top edge of the side so they aren't needed.
Another decision is whether to coat the tail & fin with a sheet of tissue to match the rest of the fuselage, the risk being that it might cause them to curl.



 

No I'm too much of a dope to do that!
Its pinned down now (after being sprayed with water) so i'll have to wait & see.

So its straight-foward to pin the bottom down while the top dries but what about the other way up? If its pinned bottom-down while the bottom dries won't it stick, even on plastic?

 

Meanwhile the Canny Canard is under the knife.
 

Leaving the right-hand upper wing pinned down overnight seems to have removed the wash-out. It had only received a single spray of 50/50 dope. Some water spray drift has also removed the wrinkles on the centre section. Now all four corners sit down so it isn't warped. It may have looked warped because the wing was only balanced on the centre struts & not squared or anything.
I'm going to do the same thing to the left-side, it also has a slight amount of wash-out, nowhere near as much as the right.
So that just leaves the question of pinning it down while the underside is wet.

Brings back childhood memories, and wide open windows as I disliked getting dizzy with Balsa Cement.

I cannot remember being affected by the fumes from balsa cement or even dope & thinners.
But of course that's what they say about Woodstock - If you can remember it you weren't there.

The dihedral complicates mounting it upside down.
I think non-stick spacers on the LE & TE would be the way to go.

By way of an experiment I pasted some tissue onto some spare balsa to measure the increase in weight.
This gave a figure of 0.03mg/sq mm per side, for the tail (both sides) it would add 0.6g so I decided to go ahead.
Without the tissue the tail weighed 3.42g, It now weighs 3.94g.
I'll now try to work out what the total increase in weight will be to balance out the this addition.

The increase in weight of the tail & fin of 0.7g. means an increase of balance weight in the nose of 2.5g. (15.1g. from 13.3g.) so increasing the total weight of the plane from 65.1g. to 67.6g. as it is at the moment (unpainted).

I am very prone to bashing into things, I regularly knock over the jar of water I soak the brushes in.
I have been doping the wings again today by doing both the undersides first & leaving them balanced upside down on the centre section then doing each side separately, pinning them down with drawing pins until they are dry.
If I left 2 days between applications it would take forever (well 8 days).
The wings are so lightly built they change so easily. Maybe the dope soaks into the woodwork, they are in their final pinning now till the morning. The tips of the unpinned sides are resting on two 13mm blocks (= 26mm) with a sanding block on top to hold them down.

For my super light weights working on the principle that the ribs themselves wouldn't bend I used to dope both top and bottom surfaces but leaving the very edge of the LE and TE un doped. Then left it to dry with the entire LE and TE supported on full length wood blocks with the LE and TE pinned or weighted down. With care the edges could be doped later once the doped tissue was fully dry.I also used a damp tissue method if using water proof (model span) tissue. The tissue would be just laid on the surface of the water and quickly removed. It was then glued onto the structure using a fine perimeter bead of PVA glue. The object was that the damp tissue did not shrink tight until the PVA had stuck the tissue to the balsa. 
The rear part of the wings of my sub 250g all foam EDF Canberra were done like that.
 
 No dope because of the foam but when painted with light coats of emulsion it was wrinkle free and water proof.